Drop inaccessible methods

These are no longer accessible and the isOwnedBy check is only used in a method that is not accessible.

Author: sebmarkbage

src/core/ReactComponent.js

@@ -416,34 +416,6 @@ var ReactComponent = {
  mountImageIntoNode(markup, container, shouldReuseMarkup);
  },
 
- /**
- * Checks if this component is owned by the supplied `owner` component.
- *
- * @param {ReactComponent} owner Component to check.
- * @return {boolean} True if `owners` owns this component.
- * @final
- * @internal
- */
- isOwnedBy: function(owner) {
- return this._owner === owner;
- },
-
- /**
- * Gets another component, that shares the same owner as this one, by ref.
- *
- * @param {string} ref of a sibling Component.
- * @return {?ReactComponent} the actual sibling Component.
- * @final
- * @internal
- */
- getSiblingByRef: function(ref) {
- var owner = this._owner;
- if (!owner || !owner.refs) {
- return null;
- }
- return owner.refs[ref];
- },
-
  /**
  * Get the publicly accessible representation of this component - i.e. what
  * is exposed by refs and renderComponent. Can be null for stateless

src/core/ReactOwner.js

@@ -126,13 +126,6 @@ var ReactOwner = {
  * @private
  */
  attachRef: function(ref, component) {
- // TODO: Remove this invariant. This is never exposed and cannot be called
- // by user code. The unit test is already removed.
- invariant(
- component.isOwnedBy(this),
- 'attachRef(%s, ...): Only a component\'s owner can store a ref to it.',
- ref
- );
  var inst = this.getPublicInstance();
  var refs = inst.refs === emptyObject ? (inst.refs = {}) : inst.refs;
  refs[ref] = component.getPublicInstance();